ENH: Only fetch submodules if building documentation.

Change-Id: Ief0a63d5d64e91e2913b37afc75877e27324034c
ENH: Bump ExternalData.cmake.

Use the latest version in ITK to avoid conflicts.

Change-Id: I6f2d1a35540a76d8e5836c61916da2a182fe3516
ENH: Make buildable as an ITKModule.

For now, only the examples can be built, not the documentation.

Rename the top level "Modules" directory to "src".

Change-Id: I57f31965b2514b38dfc3c62719fdda7624780909
DOC: point readme build instructions to the website.

Avoid duplication and getting out of sync.  Update the list of features.

Change-Id: Ia53ac1057230ad133dfcc9716dd584335ba35190
BUG: Update CreateNewExample.py for directory layout.

Change-Id: Ieaf1ef469887121e5335de9fa755a5a16c124b44
ENH: Add AppendTwo3DVolumes.

Change-Id: Ie59934bec79b49f846c655bd7f58890256c83e48
Merge topic 'Module' into master

43048db8 ENH: Add AppendTwo3DVolumes.
7a284bb9 BUG: Update CreateNewExample.py for directory layout.
15ff155b DOC: point readme build instructions to the website.
62b6cc3c ENH: Make buildable as an ITKModule.
59a56652 ENH: Bump ExternalData.cmake.
2ade079b ENH: Only fetch submodules if building documentation.